Shanghai police seized 43 kilograms of crystal methamphetamine and arrested six gang members Wednesday evening after executing four simultaneous drug raids both inside and outside the city, local media reported.

The seizure was the largest amount of crystal meth that city police have confiscated since May, according to a report on the news portal people.com.cn.

Police raided four locations at 7:45 pm Wednesday, including an apartment in the Sanlin community in Pudong New Area and an apartment in another province that was used to store drugs, the report said. Police did not disclose which province.

Officers said it is unusual for a gang to have drugs stashed in separate cities, according to the report.

Police became aware of the gang while investigating a drug dealer who appeared to have the support of a larger criminal organization. Their investigation led them to a vehicle that the gang specifically used to transport drugs.

On Monday afternoon, police trailed one of the gang members, surnamed Cao, as he drove the vehicle to an apartment 600 kilometers outside of Shanghai.

The gang used the apartment, which Cao's sister rented, to store crystal meth.

Cao picked up 25 kilograms of crystal meth and started back to Shanghai early Wednesday. Another gang member, surnamed Wu, was waiting for Cao in the Pudong apartment when he returned around 7 pm, the report said.

During the raids, police seized Cao's cargo, plus 18 kilograms of crystal meth stored at his sister's apartment. They also found 350,000 yuan ($57,435) in cash.

An analysis of the seized crystal meth determined that it was 80 percent pure. Police said the drugs they usually confiscate from street dealers are 25 percent to 70 percent pure, according to the report.

The gang had been cutting their crystal meth at the Pudong apartment to increase their supply.

Police said Cao and Wu were "core members" of the gang, while the other four were their accomplices, according to the report.